Energy providers and lawmakers are still hashing out last February's winter storm.
State climatologist Gary McManus gave on overview of the storm to an Oklahoma House committee today. He said it may not be the coldest storm on record, but it did give Oklahoma its coldest single day ever: the average temperature across the state on February 15th was -.7 degrees.
McManus said on the next night every Mesonet location on record recorded negative temperatures for the first time in history.
"When you have every site on record fall below zero, you know you're experiencing an unusual weather event in Oklahoma," McManus said.
McManus said weather scientists saw signs an extreme event could occur as early as mid-January. It had to do with changes they noticed in the polar vortex.
"We saw the possibility that some part of the mid-latitudes in the northern hemisphere could get quite cold," said McManus. "But we simply wouldn't have the capability to say where this cold air that breaks off is going to travel."
Events like these happen about six times a decade, and the movement of cold air was not the only factor. A "blocking pattern" needs to be in place, too.
"It's like if you're on the interstate and the car in front of you just stops," McManus said.
McManus said it's hard to know if cold air events like these are on the rise. More research is needed.
"This is a controversial theory," said McManus. "The idea is that the Arctic is warming up faster than the mid-latitudes, so as you start to decrease the temperature difference, the strength of that polar jet stream starts to decrease...so if you start to weaken the temperature difference, that polar jet stream starts to break down and causes cold air to spill out."
McManus clarified this is not a question as to whether or not climate change is happening; it's a question as to the possible impacts of climate change.
"The Arctic is warming up quite rapidly," said McManus. "It's just one of the theories: that it's slowing down that polar jet stream."
Lanny Nickell, Vice President of Southwest Power Pool, addressed the committee, too. SPP oversees the power grid in Oklahoma and 16 other states.
Nickell said SPP drew heavily on energy from neighboring providers during the storm.
"Thank God for the fact that we do have strong transmission interconnections with other neighbors in the east. We relied heavily on that. It kept us from having to do load shedding for much of this event," said Nickell.
Nickell said SPP did learn it needs stronger agreements and set prices with neighbors.
"The biggest neighbor to the east is Midcontinent ISO. Our arrangement with them says they will provide emergency assistance when they can at a rate of 150% of whatever the clearing price for energy is at that time. We have other agreements with other neighbors that aren't quite as clear, though."
Those relationships were what made Oklahoma fare better than Texas during the storm, however. ERCOT operates Texas's electrical grid.
"Our neighbors to the east represent many, many times more resource availability than what SPP has, and in fact what ERCOT has. I've mentioned ERCOT being about a 70,000 mega-watt system. It's a fairly large system. It's larger than SPP's. But they don't have the same kind of availability to rely on others to help when help is needed," said Nickell.
Nickell said SPP is still researching reliability and what it will cost to make any improvements to Oklahoma's grid. He said a report is expected soon.